X-ray fluoroscopy is often used for guiding electrophysiology (EP) ablation procedures. It shows the position of all catheters in real-time. 3D mapping has greatly helped the development of complex ablation procedures by showing the position of the catheter in relation to a 3D representation of the cardiac contours. However, neither tool can show the position of all catheters in relation to each other or the detailed endocardial anatomy, in real time.
The EP Navigator, which is available from Philips Healthcare, is able to confirm the position of a catheter or lead position with respect to a 2D projection of a detailed 3D cardiac anatomy in the EP intervention lab. This information can help a physician to carry out complex EP procedures with greater confidence, in a more intuitive way. Such tools may provide an automatically segmented 3D CT image. This image of the patient's cardiac anatomy is combined with live fluoroscopy data to show the exact position of all catheters. EP navigator enables a user to select a 3D anatomy (for example, left atrium and pulmonary veins) to be combined with the live fluoroscopic images. The resulting composite image provides an accurate indication of the position of all catheters in relation to the 2D projection of the detailed 3D anatomy of the heart.
Due to the complexity of the anatomy and the lack of integrated tools, complex ablation procedures are very time-consuming and usually last several hours. Success of the procedure depends on accuracy of the positioning of the catheter. Maintaining good contact between tissue and the catheter tip is important.
An electromagnetic mapping system is described in “Electromagnetic Versus Fluoroscopic Mapping of the Inferior Isthmus for Ablation of Typical Atrial Flutter” by Hans Kottkamp, M D et al., in Circulation, 2000, 102:2082-2086 (hereinafter: Kottkamp et al.). This electromagnetic mapping system consists of an external, ultralow emitter of a magnetic field, a set of 2 catheters with miniature magnetic field sensors, and a processing computer unit. Under certain circumstances described in Kottkamp et al., this electromagnetic mapping system allows to perform a mapping procedure using the electromagnetic mapping system without continuous fluoroscopy, while using additional x-ray projections, like the right anterior oblique view, if necessary.